you just kinda make a folder called thumbnail (or whatever) n put whatever image you like in it and make a page with that image and then go to index.html n put this <script> const urlParams = new URLSearchParams(window.location.search); if (navigator.userAgent.includes('Screenjesus')) { window.location.replace("https://abigblueworld.neocities.org/thumbnail/"); } </script> obv you can just replace the thumbnail folder with whatever (if it dont update try putting https://abigblueworld.neocities.org/thumbnail/index.html instead)